$L$ -Band Polarization-Independent Reflective SOA for WDM-PON Applications

An $L$-band polarization-independent reflective semiconductor optical amplifier (RSOA) is demonstrated for the first time. Optical gain of greater than 21 dB and gain flatness better than 4 dB is achieved over the $L$-band. The polarization-dependent gain estimated using a polarization resolved spectrum is less than 1 dB over the $L$-band. The measured output saturation power is $-$1.0 dBm and the noise figure (NF) is 10 dB for the packaged device. The 3-dB frequency bandwidth for the device is 1.3 GHz making it suitable for 1.25-Gb/s modulated wavelength-division-multiplexed passive optical network networks. Further, the saturation power and the NF of the RSOA were compared with an SOA of identical length.